The present invention relates generally to plumbing connectors. More specifically, the invention is directed to a waste pipe coupling for securely connecting and sealing telescoped waste pipes.
Conventional residential kitchen sinks typically include a faucet, at least one water receptor basin, and a drain for each basin. Plumbing for directing sink wastewater to a septic system of some sort, or to a sewer, is confined in a small cabinet-like area underneath the sink. The basin drain may be connected to waste pipes in the plumbing directly or via a garbage disposer. The garbage disposer grinds large solids into smaller particulates that pass from the unit and through the waste pipes. Additionally, the plumbing beneath the residential sink can include connections to a dishwasher for carrying dishwasher wastewater into the plumbing and to the sewer or septic system.
The plumbing necessary for removing the wastewater from the basins, garbage disposer, and dishwasher generally consists of interconnected pipes leading to a common waste pipe. In one prior art proposal, interconnected pipes are telescoped together and connected to each other by means of a screw ring assembly. Prior art screw ring assemblies typically include a screw ring that compresses a relatively rigid, somewhat pliable, nylon or nylon-like plastic ring against the adjoining pipes to secure them. The plastic ring has a wedge-like, or triangular, cross sectional shape. The plastic ring has a central opening that fits around a male pipe end. Plastic pipe rings are available with different central opening sizes to accommodate different male pipe end sizes. The connection is made by placing the plastic ring and the screw ring around the male pipe end and then telescoping the pipes together. The screw ring is threaded and is screwed onto a threaded end of the female pipe so that the plastic ring is wedged into engagement with both pipes by the screw ring.
One problem with these types of connections is that wastewater flows and operation of the garbage disposer and/or dishwasher cause vibrations, shock loadings on the parts, and wrenching forces that, in turn, cause the prior art screw ring assemblies to loosen. The screw ring threads do not lock when the screw ring is initially tightened. The plastic ring is plastically deformed as it is wedged into place. The seal ring does not accommodate relative movement between the waste pipes that is created by vibrations in the systems. Moreover, the plastic deformation of the seal ring results in the seal ring failing to maintain pressure on the locking ring that creates frictional resistance to loosening the screw ring. The vibrations cause the screw ring to back away from the plastic ring along the pipe thread so that seal ring wedging forces are removed. Over time and use, these pipe connections are prone to leak. Moreover, the leakage generally worsens over time with further continued use.
Another problem with these screw assemblies is that multiple 360xc2x0 rotations are required to complete assembly of the telescoped pipe connection. Since the plumbing is generally confined to a small area that may contain several interconnected pipes, the screw ring assembly is oftentimes difficult to access. Complete, continuous rotation by a wrench is often impeded by the other plumbing fixtures, pipes and under sink structural members. Whether the pipe joint is assembled under a sink or not, the installer is often unable to judge how tightly the screw ring has engaged the plastic ring and wedged it into place. Consequently, in some installations the screw rings were tightened too much while in others the screw rings were not tightened enough. When the screw ring was tightened too much, the plastic ring was over-compressed and distorted by the screw ring. The resulting pipe joint connection leaked. When the screw ring was too loose, the pipe joint leaked immediately or in a relatively short time because the parts were not properly engaged.
The present invention provides a new and improved under-sink waste pipe system that is so constructed and arranged that sealing failures due to vibrations caused by associated equipment are minimized, leakage resulting from waste pipe seals being compressed too forcefully or not forcefully enough are completely eliminated, and a tactile indication of proper installation is provided to the waste pipe installer.
The present invention concerns an under-sink waste pipe coupling for coupling a first, relatively smaller, waste pipe, and a second, relatively larger, waste pipe telescoped together wherein a softly resilient seal ring that occupies a space between the waste pipes and seals the juncture of the waste pipes; a locking ring compresses the sealing ring into resilient sealing engagement with the waste pipes; and, a latching mechanism secures the locking ring in place with the seal ring resiliently compressed a predetermined degree.
The first waste pipe has an end portion defining an outer cylindrical surface that extends into the second waste pipe. The second waste pipe has an end flange structure surrounding an end opening and defines a sealing face surrounding the first waste pipe cylindrical surface when the first waste pipe extends into the end opening. An inner surface of the second waste pipe is substantially spaced apart from the outer cylindrical surface of the first waste pipe.
The softly resilient seal ring adapts the first, relatively smaller, pipe for coupling to the second, relatively larger, pipe. The softly resilient seal ring engages the end flange structure sealing face and extends radially inward to engage the outer cylindrical surface of the first waste pipe. The seal ring contacts the first waste pipe outer surface and the end flange sealing face along bands of sealing contact.
The locking ring is secured to the end flange structure and defines an opening surrounding the first waste pipe, a force transmitting surface surrounding the opening, and a body section extending axially from the force transmitting surface. The force transmitting surface resiliently deforms the seal ring and urges the seal ring toward resilient engagement with the outer cylindrical surface of the end portion and the end flange sealing face. The seal ring sealingly engages the sealing face and sealingly and frictionally engages the end portion.
The latching mechanism maintains the locking ring secured to the end flange structure and comprises at least first and second latching projections, on one of the locking ring or end flange structure, that extend towards the other of the locking ring or end flange structure, and projection guiding cam surfaces formed in the other of the locking ring or end flange structure. The projection guiding cam surfaces each form a notch-like latching recess where the projection is disposed when the waste pipes are assembled together. The projection is resiliently urged into the recess by the seal ring to maintain the locking ring latched to the end flange structure and the seal ring resiliently compressed a predetermined degree.
In a first embodiment of the waste pipe coupling, the force transmitting surface of the locking ring engages the seal ring to resiliently deform the seal ring. In a second embodiment of the waste pipe coupling, the force transmitting surface of the locking ring engages a compression flange on the fist pipe to resiliently deform the seal ring.
The latching recess and cam surface are constructed and related so that the projection snap moves into the recess, providing a tactile indication that the pipes are properly assembled together.
In another embodiment of the invention an under-sink waste pipe system is provided that comprises first waste pipe having a first end communicating with a sewer or septic system, a trap pipe connected to the first waste pipe, a softly resilient seal ring for sealing the first waste pipe to the trap pipe, a locking ring associated with the seal ring for resiliently compressing the sealing ring onto sealing engagement with the first waste pipe and the trap pipe, and a latching mechanism for maintaining each locking ring secured in place with each sealing ring compressed to a predetermined degree.
The latching recess and cam surface are constructed and related so that the projection snaps into the recess, providing a tactile indication that the pipes are properly assembled together.
In one embodiment, the seal ring extends into the second waste pipe between the outer cylindrical surface of the first waste pipe and the inner cylindrical surface of the second waste pipe and the inner cylindrical surface of the second waste pipe to stabilize the first and second waste pipes. The seal ring may extend through the locking ring opening between the first waste pipe and the locking ring opening to further stabilize the coupling.
Additional features and advantages will become apparent from the following description of an illustrated embodiment made with reference to the accompanying drawings which form part of the specification and wherein: